Impact crusher



April 18, 1939. w. H. SCHACHT IMPACT CRUSHER 4 Sheets-Sheet 1 Filed Jan.7, 1953 4 Sheets-Sheet 2 W. H. SCHACHT IMPACT CRUSHER Filed Jan. 7, 1933April 18, 1939.

4 Sheets-Sheet 3 f W Y m j INIQQ W/ i H w w wfi April 1939- w. H.SCHACHT IMPACT CRUSHER Filed Jan. 7, 1935 4 Sheets-Sheet 4 Zita/12496.}

- in impact crushers.

Patented Apr. 18, 1939 PATENT OFFICE IMPACT CRUSHER William H. Schacht.Painesdale, Mich. Application January 7, 1933, Serial No. 650,597

21 Claims. (Cl. 83-46) My invention relates to a crusher or pulvizer andit has for one object the provision of a machine for reducing rock, oreand the like. Another object is the provision of an improvement Anotherobject is the provision of an associated crushing and screening meansfor unitary operation. Another object is the provision of an improvedcrushing and screening installation particularly adaptable for closedcircuit crushing. Another object is the provision of means for takingout uncrushable particles, for example native copper, from the closedcrushing and screening circuit. Another object is the provision of meansfor re-feeding oversize to an impact crusher. Other objects will appearfrom time to time in the course of the specification and claims. l

I illustrate my invention more or less diagrammatically in theaccompanying drawings, wherein a Figure 1 illustrates a plan view;Figure 2 is a side elevation; Figure 3 is a front elevation of parts insection on the lineI-lofFlgure 2;

Figure 4 is a section on the line 4-4 of Figure 1;

Figure 5 is a section on the line 8-! of Figure 4;

Figure 6 is a section on the line 6-! of Figure 7;

Figure 7 is a section on the line l--l of Figure 6; 1 I

Figure 8 is a section similar to Figure 7 through a variant'form of thedevice;

Figure 9 is a vertical section through a variant form of the devicesimilar to Figure 4; and

Figure 10 is.a section on the line Ill-l0 of Figure 9 of a variant formof the device.

Like parts are indicated by like symbols throughout the specificationand drawings.

Referring to the drawings, A generally indicates any suitable fixedsupporting structure upon which may be mounted any suitable supportingmember A held in place for example by the bolts A.

I indicates an impeller spindle to which is secured the impellerstructure generally indicated as 2 which includes a disc B and alaterally spaced ring B the ring and disc being connected by a pluralityof impeller vanes or struts B which are clearly shown in section as inFigure 5. P0sl-' tioned adjacent and preferably abutting against theimpeller vanes B are the impeller striking or wearing plates B of whichthree are shown in Figures 5 and '7 and only two in Figure 8, it beingunderstood that the number may be varied. The

impeller plate B may include a collar or hub 13 surrounding the end ofthe impeller shaft l the parts being held against movement as by thebolt B and the nut B and key B". Any suitable means may be employed forrotatably supporting the impeller shaft or spindle I as for example thepedestal and hub bearing bed plate A with its pedestal supports C inwhich may be mounted the shaft or spindle bearing sleeve 0 held in placeas by the clamp members C which may be tightened as by the bolts 0* andnuts (2*. Positioned within the bearing sleeve C are any suitable rollerbearings C within the inner race of which is positioned the shaft orspindle I. C indicates a terminal driving pulleyfor the shaft or spindlewhich may be secured to the end of the spindle l whereby the spindle andthe impeller may be rotated. C indicates a main bearing adlusting sleevewithin the spindle bearing sleeve C. It will be clear from the figuresthat whereas the member B is shown as a disc the member B is a ringlaterally spaced from and opposite to the periphery of the disc B,whereby, as will later appear, material may be fed for free gravitalfall between the disc B and ring B to the wearing plate B. I

Surrounding the impeller structure is the impeller housing structuregenerally indicated as D. D is the impeller housing bearing which may bemounted in any suitable way on the base A. D? indicates an impellerhousing ring bearing hub. D indicates any suitable anti-friction bearingand D is the impeller housing driving sprocket. The housing includes aflat portion D which is outwardly flared as at D and terminates in aspecies of circular track D which may be supported upon trunnion rollersD rotatable upon adjustable trunnion rollerframes D which may beadjusted as by the screw device D upon the trunnion roller base D Theinterior. of the impeller housing is provided with any suitable ,linerplates D as shown in Figure 4.

. ure 4 the striker plates lie in the plane of rotation of the impellerwearing plates B and any material which passes between the impellerplates or which is driven from the impeller plates by the crushing ordisintegrating impact, is received by the striking plates. As will laterappear, the rate of feed and the rate of rotation is such that materialcannot drop through the path of movement of the striking plates withoutreceiving a crushing or disintegrating impact, the action of which isindicated for example in Figures 4 and 5.

Further secured to the impeller housing structure is a circumferentialgrizzly or screen generally indicated as G. It may be bolted orotherwise suitably secured to the outer edge of the impeller housing asat G and is provided with a forward circumferential side ring GAssociated with the rotating grizzly structure are a plurality ofelevator buckets Ci which therefore rotate unitarily with the impellerhousing. Any material which falls to pass through the grizzly or screenis picked up by the buckets and upwardly conveyed until aligned with anddischarged upon the surfaces of the oversize return chutes G The mainline of feed is along the feed chute G and the oversize chutes G returnthe oversize picked up by the buckets G to .the main line of feed alongthe chute G The result is a closed crushing and screening circuit, theonly normal escape from the circuit being through the screen.

However, it may happen, as in screening copper ore, that uncrushablemasses of native copper may accumulate in the circuit. Similarly,uncrushable masses may accumulate in the crushing and screening of othermaterials. In order to permit the removal of such material I provide arejector chute generally indicated as H which may be pivoted as at H andwhich may be moved inwardly into the line of feed or delivery along thechute G whereby the feed, or oversize, may be temporarily by-passed tothe picking deck H", for the removal of the undesired particles. WhereasI have shown a single pair of links H it will be realized that I mayemploy additional links if desirable. The deck IF may be pivoted as at Hwhereby it may be dropped into the dotted line positiori as at 1-1,after the picking has been completed. B indicates a picking deck returnchute, which delivers the particles on the deck back into the crushingand screening circuit. As it is possible that some particles may boundor rebound within the circle. defined by the impeller surfaces 13forming a spiral of material which is not being properly disintegrated,I provide a fixed or stationary striking plate J, shown for example inFigure 5, which is located under the upper portion of the inner circleformed by the path of the revolving impeller plates B and which ispreferably at right angles to the plane of the impeller, and whichtherefore intercepts the swirl of stray material swept around by theimpeller, that has not succeeded in passing through the circular path ofthe impeller striking plates B This material is deflected, by the aid ofgravity, with sufficient velocity into the path of the impeller plates,to rejoin the general crushing or disintegrating cycle. The plate J mayalso have a certain further disintegrating effect on such strayfmaterial as contacted. The rotary motion will be stopped and thematerial will fall vertically or nearly so, into the path of theimpeller plates, with the aid of gravity and with the aid of the airvelocity caused by the fan action of the impeller, which tends to suckor drive air radially outwardly away from the center of the impellerstructure.

K indicates a hinged shield for closing the forward face of the machine.It is hinged for example by the hinges K which in turn are secured tothe supporting posts K rotatable in any suitable bearings K one hingedhalf of the shield K is omitted from Figure 3 in order to show theinterior of the device. In the machine as employed, two hinged shieldsare employed each mounted on a post K the post being situated onopposite sides of the front of the machine. Feed chutes are attached toone half of the shield only, so that inspection can be made withoutdisturbing the chutes. It

will be understood that by swinging the shields aside the entireinterior of the structure is exposed to view, which is a help ininspection. K indicates any suitable outer shell or housing It will beunderstood that about the grizzly, which may be open at the bottom as atK to discharge material passing through the grizzly or screen. It isindicated as having inclined lower sides K which may be used to serve aslimiting chutes.

Referring to Figure 1, I preferably employ a plurality of motors. Iillustrate for example a primary motor 0 for the impeller, which isprovided with a pulley O slotted to receive a plurality of belts O whichserve to drive the pulley C of the impeller shaft. A secondary motor 0through any suitable gear reducer O maydrive the sprocket O and therebythe chain 0 passing about the sprocket D of the impeller housing. -Iillustrate in Figures 9 and 10 a variant form in which I employ twoimpellers, a primary im-.

peller and a secondary impeller. These impellers are driven at a rapidrate of speed and in opposite directions of rotation. Referring to thesedrawings, M indicates the primary impeller spindle with its drive pulleyM its impeller disc M impeller ring M struts M and wearing or impactplates or faces M N indicates a driving sleeve for the secondaryimpeller, with its drive pulley N secondary impeller disc N secondaryimpeller ring N connecting struts N and impact members N Since theremaining parts of the device have the same function as in the otherforms I will not describe or show the parts in detail.

It will be realized that whereas I have described and shown a practicaland operative device, nevertheless many changes might be made in thesize, shape, number and disposition of parts without departing from thespirit of my invention. I therefore wish my description and drawings tobe taken as in a broad sense illustrative and diagrammatic rather thanas limiting me to my specific showing.

The use and operation of my invention are as follows:

Broadly stated, my method and apparatus are for the purpose of reducingthe size of ore, rock or other material, by disintegrating it by aseries of impacts with the striking or wearing plates B which are fixedradially, or nearly so, to the vanes or cross braces of the impeller.The impeller includes the circular disc B which is mounted centrally atthe end of the spindle I. The impeller and the impeller housingstructure generally indicated as D rotate about a common axis, but areseparately rotated and preferably at greatly different speeds. Materialmay be fed down by the main feed chute G and is thereby delivered intothe space between the plate or disc B and the ring B of the impeller.The material falls by gravity and preferably the chute is of sufficientlength or the height of' initial feed is sufiicient to impart a verysubstantial gravity acceleration.

Furthermore, the vanes of the impeller have a fan effect which tends todischarge air radially outwardly from the inner space of the impellerand this air movement further speeds the falling particles after theypass below the axis of rotation of the impeller. Therefore the materialto be reduced is fed at a high rate of speedthrough the open end of theimpeller on its downwardpath from the feed chute and,-as it passesbetween the disc 3 and the ring B into the line of movement of thestriking plates B each particle receives a disintegrating impact. Theimpeller'revolves at a high rate of speed about its horizontal axis, atsuch a rate that in order to intercept an impact of all or moresubstantially all of the falling particles one, two or three or more ofthe members B may be necessary. The feed chute G may be steeplyinclined, at an angle of degrees more or less. The falling particlesattain suflicient velocity relative to the velocity of the impellerstriking plates B to reach the path of the impeller plates before theyare struck and the rates of rotation and the length of fall arepreferably so timed and arranged that the particles make a full andcomplete contact with the faces of the striking plates B rather thanmerely being struck by the top edges only.

The members B serve as reinforcing vanes and struts. In order to preventvibration or centrifugal strain caused by the rotation of an unbalancedmember I provide balancing washers 3 which may be threaded upon thebalancing assembly pin B their displacement being prevented by anysuitable nut B".

In the form of Figures 5 and 7 I illustrate the employment of three ofthe impact members B one for each of the struts. In Figure 8, where Iwish to employ but two of the members B I illustrate four of the struts13 arranged in pairs. Two of the struts extend all the way in to theinner edges of the members B The other struts do not extend so far inand the impeller is preferably driven at such a rate that each impactmember or plate B prevents the contact of the falling particles with thefollowing strut. That is to say, the following strut is positionedradially outwardly a sufllcient distance so that any falling particlewhich could meet it is contacted by the preceding member B The particleswhich clear one of the members 13 have not moved far enough when thefollowing strut comes in line to be hit by it, but will be hit by thefollowing plate 13 In other words, if the velocity of the feed is thatof the impeller, then the secondary strut must be set farther from thecenter of the impeller than the striking plate strut by a distance equalto itsdistance from the striking plate strut, in order not to interferewith the feed. For the reduction of fine sized feed of ore, rock, etc.,four or more impeller striking plates may be employed.

The annular ring B serves not only to support the ends of the struts buthas the secondary function of confining and directing the passage of thebroken ore or rock and also to create a definite air circulation throughthe impeller, to help carry the material or particles therethrough.

The reflector ring E with the plates E surrounds and is concentric withthe impeller, revolving about the same axis. After impact with theimpeller striking plates B the broken or partly disintegrated materialinstantly attains a high velocity, due to centrifugal force acting on itby the rotating impeller, and is thrown out- Wardly from the impellerand downwardly and to the return chute H outwardly against the wearingplates E of the reflector ring. Centrifugal force, combined with theforce of gravity and the force of the air current set up by theimpeller, all act on thematerial in the same general downward direction,giving it ahigh velocity which directs the particles against the wearingplates E, resulting in a secondary reduction of the material.

There is some further reduction of particles of ore or rock caused bytheir striking each other in passing from the impeller to the reflectorring plates and vice versa. There is also some further reduction causedby particles bounding or rebounding from the reflector ,plates and againgetting into the path'of the revolving impeller striking plates. Thestationary striking plate J also has some disintegrating eiiect althoughits primary purpose is to intercept the swirl of stray material sweptaround by the impeller, that has i not succeeded in passing through thecircular path of the impeller striking plates. This stray material isdirected back into the path of the plates B.

For screening the disintegrated product I provide a circumferentialscreen or grizzly which rotates in unison with the impeller housing. Theparticles which are sufficiently reduced will pass through the screen orgrizzly to any suitable conveying means. The oversize particles whichcannot pass through the grizzly are picked up by the buckets G and arethereby returned to the over-. size return chutes G and thus to the feedchute G As the result is a closed screening and disintegrating circuit,any non-reducible material should be removed from the circuit. Forremoving such material, such as tramp iron, steel, or native copper, orthe like I may intercept the flow of the oversize return feed by thechute H,

without shutting down the machine. intercepts the oversize return anddirects it to the picking table H. The uncrushable material is therepicked and removed and the residue may be returned by tilting the tableH to deliver it This ready means of removing uncrushable material makesunnecessary the use of a magnetic pulley for the removal of tramp ironor steel. Such foreign material can It simply enter the machine withoutcausing injury, be-

cause the clearance between the impeller and reflecting ring plates isseveral times the opening of other crushers making a product the samesize. In other words, all that such uncrushable particles will do is totravel around the closed circuit without being disintegrated orscreened. When there is s'ufllcient' accumulation of such particles tomake it worth /while, the rejector chute H is simply moved into positionand such particles will then be delivered to the picking table IP forremoval by picking. The construction of the machine permits partial orentire removal of the impeller, with its spindle shaft I, bearing sleeveand driving pulley C", to facilitate replacement of the striking platesof the impeller and the reflecting ring wearing plates, without furtherdismantling the machine. This may be done by simply sliding the impellerspindle or shaft sleeve with the shaft and impeller in place through theimpeller housing ring beartightens and holds the wedge-shaped strikingplates 13 in place. To change the plates it is necessary to tap themattheir outer edge to loosen them.

A stationary or non-rotated hinged shield K is provided for closing theopen end of the revolving impeller housing, and for supporting the feedand discharge chutes. The hinged chute is formed of two parts or halves,the feed or dis-' charge chutes being mounted upon one half onlythereof.

The control of the intensity of the impact forces is a matter ofimportance. For a given diameter of impeller and a given speed, the in-'tensity with which the partly reduced material is thrown out against thereflector ring, wear plates or the secondary impeller striking plates,by the impeller is controlled by the variation of the angle between aradial line drawn through the center of the impeller and some point onthe plane of the face of the impeller striking plate. The intensity maytherefore be varied by merely changing the angle of the faces of themembers B opposed to the material. The same effect is obtained byvarying the faces M or N ofthe variant form. The intensity may also becontrolled by varying the speed of the impeller and by varying thediameter of the impeller. The combination of these varying factors makespossible a control of the breaking force to suit the requirements forbraking ores or rock of different hardness or size in order to get thegreatest amount of work out of a givenpower input.

Referring to the form of l lgures 9 and 10, I illustrate a device havinga primary and a secondary impeller which are separately driven and arerotated in opposite directions of rotation. The action of the machinewith this modification is identical with the action of the form. ofFigures 1 and following, except that the ore or other material, insteadof being directly thrown from the striking plates 13 of the primary im--peller against the reflector ring plates after the primary reduction,are thrown against the striking.plates of the secondary impeller whichrevolve in an opposite direction. The impact with the striking plates ofthe secondary impeller makes the secondary reduction. After thissecondary reduction, the broken ore or rock is' thrown against thereflector ring wear plates, E and the process continues as previouslydescribed.

Ample clearance space is provided between the inner circular path of thestriking plates of the secondary impeller and the outer circular pathdescribed by the striking plates of the primary impeller, so as to passany non-reducible foreign material without injury to the impellers. Thesecondary impeller is shown as having several times as many strikingplates as the primary impeller, and it may be revolved at the same speedor at a lower or higher speed than the primary impeller. The extent ofthe secondary reduction may be controlled by varying the speed of thesecondary impeller, or by varying the angle that the face of theimpeller striking plate makes with a radial line drawn through it.

In defining the operation of my device I may employ the term inner pathas the inner margin or inner face of the path described by the impactmembers as they run in their normal operation, the cylindrical surfacedefined by that part of the impeller members nearest their center ofrotation. The outer path is the corresponding cylinder defined by theparts of the impellers farthest from their center of rotation. While Isay cylindrical for purpose of illustration, it will be understood thatI do not wish to be limited to any particular figure or shape, as thepath might be conical or otherwise shaped.

I claim:

1. In an impact crusher, an impeller, a reflecting ring surrounding saidimpeller, and means for rotating said impeller and said reflecting ringconcentrically about a generally horizontal axis, one or more impactmembers mounted upon and rotating with said impeller, means for feedingmaterial by gravity into the space defined by the path of said impactmembers, and for causing it to fall freely by gravity through the innerpath of the impact members, into the line of movement of the impactmembers, and rotary screening means for receiving the particlesdischarged from said impact members and reflector ring, means forre-feeding to said impact members the particles which fail to passthrough the screening means, 'means for withdrawing particles from thefeeding circuit so formed, including a reiector chute, and means formoving it into the line of feed.

2. In an impact crusher, an impeller, a reflecting ring surrounding saidimpeller, and means for rotating said impeller and said reflecting ringconcentrically about a generally horizontal axis,

- one or more impact members mounted upon and rotating with saidimpeller, means for feeding material by gravity into the space deflnedby the path of said impact members, and for causing it to fall freely bygravity through the inner path. of the impact members, into the line ofmovement of, the impact members, and rotary screening means forreceiving the particles discharged from said impact members andreflector ring, means for re-feeding to said impact members theparticles which fail to'pass through the screening means, means forwithdrawing particles from the feeding circuit so formed, including arejector chute, and means for moving it into the line of feed, a pickingdeck to which said rejector chute delivers and a return chute adaptedtoreceive material from said picking deck and to return it to thecrusher.

3. In an impact crusher, an impeller, a reflecting ring surrounding saidimpeller, and means for rotating said impeller and said reflecting ringconcentrically about a generally horizontal axis, one or more impactmembers mounted upon and rotating with said impeller, means for feedingmaterial by gravity into the space defined by thepath of said impactmembers, and for causing it to fall freely by gravity through the innerpath of the impact members, into the line of movement of the impact.members, and rotary screening means for receiving the particlesdischarged from said impact members and reflector ring, and means forre-feeding to said impact members the particles which fail to passthrough the screening means, including elevator buckets mounted formovement with said rotary screening means and a feed chute adapted toreceive the material discharged by said buckets.

4. man impact crusher an impeller rotatable about a generally horizontalaxis. and means for rotating it, a pluraliiy of impact members mountedupon said impeller, said impact members being spaced radially from theaxis of said impeller and being spaced circumferentially about saidimpeller, means for directing material into the space defined by thepath of the impact mem-' bers, said impact members being provided withimpact faces adapted to engage the particles falling. therebetween, areflector ring surrounding the impeller and lying in the general planeof the impact members and adapted to receive particles centrifugallydelivered by the impact members, said reflector ring having a free edge,whereby the crushed partcles can escape readily beyond said reflectorring after crushing, a rotary grizzly adjacent said reflector ring,means for directing crushed material from said reflector ring to therotary grizzly, and means for rotating said reflector ring and rotarygrizzly in unison.

5. In an impact crusher an impeller rotatable about a generallyhorizontal axis, and means for rotating it, a plurality of impactmembers mounted upon said impeller, said impact members being spacedradially from the axis of said impeller and being spacedcircumferentially about said impeller, means for directing material intothe space defined by the path of the impact members, said impact membersbeing provided with impact faces adapted to engage the particles fallingtherebetween, a reflector ring surrounding the impeller and lying in thegeneral plane of the impact members and adapted to receive particlescentrlfugally delivered by the impact members, said reflector ringhaving a free edge, whereby the crushed particles can escape readilybeyond said reflector ring after crushing, a rotary grizzly adjacentsaid reflector ring, means for directing crushed material from saidreflector ring to the rotary grizzly, and means for rotating saidreflector ring and rotary grizzly in unison about an axis generallyconcentric with the axis of rotation of the impeller. Y I

6. In an impact crusher an impeller rotatable about a generallyhorizontal axis, and means for rotating it, a plurality of impactmembers mounted upon said imp'eller, said impact members being spacedradially from the axis of said impeller and Ming spacedcircumferentially about said impeller, means for directing material intothe space defined by the path of the impact members, said impact membersbeing provided with impact faces adapted to engage the particles fallingtherebetween, a reflector ring surrounding the impeller and lying in thegeneral plane of the impact members and adapted to receive particlescentrifugally delivered by the impact members, said reflector ringhaving a free edge, whereby the crushed particles can escape readilybeyond said reflector ring 'after crushing, a rotary grizzly adjacentthe reflector ring, and a guide ring adapted to receive the materialdischarged from the reflector ring and direct it to the rotary grizzly.

7. In an impact crusher an impeller rotatable about a generallyhorizontal axis, and means for rotating it, a plurality of impactmembers mounted upon said impeller, said impact members being spacedradially from the axis of said impeller and being spacedcircumferentially about said impeller, means for directing material intothe space deflned by the path of the impact members, said impact membersbeing provided with impact faces adapted to engage the particles fallingtherebetween, a reflector ring surrounding the impeller and lying in thegeneral plane of the impact members and adapted to receive particlescentrifugally delivered by the impact members, said reflector ringhaving a free edge, whereby the crushed particles can escape readilybeyond said reflector ring after crushing, a rotary grizzly adjacent thereflector ring, a guide ring adapted to receive the material dischargedfrom the reflector ringand direct it to the rotary grizzly, and meansfor unitarily rotating the guide ring, reflector ring and grizzly aboutan axis generally concentric with the axis of rotation of the impeller.

8. In an impact crusher a rotary impeller mounted for rotation about agenerally horizontal axis and means for rotating it, and a unitaryrotatable housing member surrounding said impeller and rotatable about agenerally concentric axis, and independent means for rotating it, areflector ring mounted on said housing in the same general plane as theplane of rotation of the impeller member, a rotary grizzly mounted uponand rotatable with said rotary housing, and movable means for closingthe forward face of the rotatable housing.

9. In an impact crusher a rotary impeller mounted for rotation about agenerally horizontal axis and means for rotating it, and a unitaryrotatable housing member surrounding said impeller and rotatable about agenerally concentric axis, and means for rotating it, a reflector ringmounted on said housing in the same general plane as the plane ofrotation of the impeller, a

rotary grizzly mounted upon and rotatable with said rotary housing, andmovable means for closing the forwardiace of the rotatable housing,including a fixed housing and a closure therefor.

10. In an impact crusher, a rotary impeller mounted for rotation about agenerally horizontal axis and means for rotating it, a reflector ringmounted for rotation in the same general plane as the plane of rotationof the impeller said impeller including impact members adapted to directimpacted particles centrifugally against the reflector ring for a secondcrushing impact, and a rotary grizzly mounted for rotation in unisonwith said ring, and means for directing particles from the reflectorring to the rotary grizzly, the reflector ring having a free edge,whereby the crushed particles can escape readily from the ring aftercrushing.

11. In an impact crusher, a rotary impeller mounted for rotation about agenerally horizontal axis and means for rotating it, a reflector ringmounted for rotation in the same general plane as the plane of rotationof the impeller, a rotary grizzly mounted for rotation in unison withsaid ring, a chute adapted to deliver material through the plane of saidgrizzly and directly into the space deflned by the path of movement ofthe impeller, and means associated with the grizzly, for delivering intosaid chute the oversize material for recrushing.

12. In an impact crusher, a rotary impeller mounted for rotation about agenerally horizontal axis and means for rotating it, a reflector ringmounted for rotation in the same general plane as the plane of rotationof the impeller, a rotary grizzly mounted for rotation in unison withsaid ring, and a guiding ring adapted to direct the crushed materialwhich escapes from the reflector ring to the rotary grizzly.

13. In an impact crusher, a rotary impeller mounted for rotation about agenerally horizontal axis, said impeller including a shaft and a platemounted at one end thereof, impact members associated with said plate, areflector ring surrounding said impeller and lying in the generalvertical plane of the impact members, means for supporting and rotatingsaid ring including an open rotary housing surrounding said ring andextending to the rear of the impeller plate, and guiding meansassociated with said housing and extending closely adjacent to theperiphery of the plate, adapted to prevent the penetration of materialto the rear of said plate.

14. In a two-stage impact crusher, means for imparting a primarycrushing impact to freely falling particles, which includes a singlerotatableimpeller, a plurality of primary impact members normally fixedupon said impeller, spaced radially from the axis of the impeller, andspaced circumferentially about the impeller, and means for gravitallyprojecting an unconsolidated stream of particles along a defined andunobstructed path, into the path of movement of the impact members ofthe impeller at a velocity sufficient to carry substantially eachparticle of the stream fully into said path, whereby substantially eachparticle is positioned to be squarely impacted by the impact face of theimpact members of the impeller, means for rotating said impeller at suchspeed and momentum as will cause adequate crushing impacts, and at thetime of such impacts will present the faces of its primary impact,

members to squarely impact the particles which penetrate into the pathof the primary impact members, and means for imparting a secondarycrushing impact to the particles crushed by the primary impact, whilesaid particles are in flight from the impeller and its impact members,including an imperforate breaker member 'positioned radially outwardlyfrom the impeller at a distance from the periphery of the impellersubstantially greater than the diameter of the maximum size 01'particles being crushed, and lying in the plane of the primary impactmembers, and adapted to receive the particles centrifugally delivered bythe primary impact members thereagainst, said breaker member having afree edge and being adapted to permit the ready gravital removal fromthe face thereof of the particles impacted thereagainst.

15. The structure of claim 14 characterized by the employment, as abreaker member, of an imperi'orate member surrounding the impeller andlying in the general plane of the impeller and adapted directly toreceive all the particles centrifugally delivered by the impeller, saidbreaker ring having a free edge whereby the crushed particles can escapereadily from the edge of the ring after crushing.

16. The structure of claim 14 characterized by the employment, as abreaker member, of a continuous-ring surrounding the. impeller and lyingin the general plane of the impeller and adapted directly to receive allthe particles centrifugally delivered by the impeller, said breaker ringhaving a free edge whereby the crushed particles can escape readily fromthe edge of the ring after crushing, and a combined rotary grizzly andelevator, and means for rotating it about an axis generally concentricwith the 'axis of rotation of the impeller, and means for returningover-size particles from said grizzly and elevator into the line ofprojection, whereby such oversize particles re-enter the path ofmovement of the primary impact members.

17. The structure of claim 14 characterized by the employment, as abreaker means, of a continuous ring surrounding the impeller and lyingin the general plane of the impeller and adapted directly to receive allthe particles centrifugally delivered by the impeller, said breaker ringhaving a free edge whereby the crushed particles can escape readily fromthe edge of the ring after crushing, and a combined rotary grizzly andelevator, and means for rotating it about an axis generally concentricwith the axis of rotation of the impeller, and means for returningover-size particles from said grizzly and elevator into the lineprojection, whereby such oversize particles re-enter the path ofmovement of the primary impact members, and means for rejectinguncrushable material from the return circuit thus provided.

18. In an impact crusher, a rotary impeller mounted for rotation about agenerally horizontal axis, and a rotary combined grizzly and elevatormounted for rotation about a generally concentric horizontal axis, saidgrizzly and elevator being axially spaced along the common axis, andlying in a vertical plane at one side of the impeller, and a breakerring surrounding said impeller and lying in the plane of said impellerbut rotating in unison with and coaxial with the combined grizzly andelevator, means for delivering material from the plane of the breakerring to the plane of the combined grizzly and elevator, the breaker ringhaving a free edge adapted for the ready gravital escape of materialtherefrom, and a feed chute adapted for the unobstructed guiding anddelivery of an unconsolidated stream of material at high velocity to therotary impeller through the path of its impact portions, the upper endof said chute being positioned at a level substantially higherthan theuppermost portion of the impeller, said chute inclining steeplydownwardly through the open interior of the combined grizzly andelevator and terminating at a point adjacent the vertical plane definedby the edge of the impellerclosest to the grizzly and elevator.

19. The structure of claim 14 characterized by the employment, as agravital projecting means, of a chute adapted to direct a stream of theparticles to be crushed into the space defined by the inner edges of theimpact members, whereby said particles are directed downwardly andwithout obstruction into the path or said impact members through thecircular path defined by said inner edges.

20. In an impact crusher, a pair of concentric rotatable impellers andmeans for rotating them about their concentric axes in oppositerotational directions, each said impeller including a plurality ofimpact members spaced radially from the axis of the impeller, and spacedcircumferentially about the impeller, the impact members of the twoimpellers being spaced by different radial distances from their commoncenter of rotation, and means for gravitally directing an unconsolidateddeflned stream of material into the path of movement of the impactmembers of the inner impeller, at a velocity sufficient to carrysubstantially each particle of the stream fully into said path, wherebysubstantially each particle is positioned to be squarely impacted by theimpact face 0! the impact members of the impeller, the spaces betweenthe impact members of the inner impeller being of 'sufllcient peripheralextension to permit the impacted particles to be delivered centrifugallyoutwardly therethrough and into the path of the impact members of theouter impeller, and imperforate breaker means positioned radiallyoutwardly from the outer impeller, at a distance from the periphery ofsaid impeller substantially greater than the diameter of the maximumsize of particles delivered outwardly from said impeller, and lying inthe plane of the impact members, and adapted to receive the particlescentrifugally delivered by the primary impact members thereagainst, saidimperforate breaker member having a free edge.

21. In a two-stage impact crusher, means for imparting a primarycrushing impact to freely failing particles, which includes a singlerotatable impeller. a plurality of primary impact members normallyradially maintained when in opera-' tive position upon said impeller.spaced radially from the axis of the impeller, and spacedcircumierentially about the impeller, and means for gravitallyprojecting an unconsolidated stream of particles along a defined andunobstructed path, into the path of movement of the impact members ofthe impeller at a velocity suilicient to carry substantially eachparticle oi the stream fully into said path, whereby substantially eachparticle is positioned to be squarely impacted by the impact face of theimpact members of the impeller, means for rotating said impeller at suchspeed and momentum as will cause adequate crushing impacts, and at thetime of such impacts will present the faces of its primary impactmembers to squarely impact the particles which penetrate into the pathof the primary impact members, and means for imparting a secondarycrushing impact to the particles crushed by the primary impact, whilesaid particles are in flight from the impeller and its impact members,including an' imperforate breaker member positioned radially outwardlyfrom the impeller at a distance from the periphery of the impellersubstantially greater than the diameter of the maximum size of particlesbeing crushed, and lying in the plane of the primary impact members, andadapted to receive the particles centrifugally delivered by the primaryimpact members thereagainst, said breaker member having a free edge andbeing adapted to permit the ready gravital removal from the face thereofof the particles impacted thereagainst.

WILLIAM H. SCHACHT.

